The olefin stream employed in the standard refinery alkylation processes is principally that obtained from the thermal or catalytic cracking of higher boiling hydrocarbons or from a hydrocarbon coking operation. This olefin stream often contains a significant amount, e.g. about 1% or more, of dienes. Even this small amount of diene in the feed to the alkylation process has been widely recognized as being undesirable for the one reason, among others, that it results in a greatly increased consumption of acid made necessary by the formation of tarry acid-diene condensation products. Other olefin streams may contain greater amounts of dienes, such as 50% or greater dienes.
A process employing a novel catalyst has now been found that results in the selective hydrogenation of the diene components without the undesirable hydrogenation of the olefins.